Fluidic press control system

ABSTRACT

A control system for a press in which the press has a fluidactuated clutch and brake mechanism with a fluid-operated control valve and a fluidic system for controlling the supply of actuating fluid to the control valve, said fluidic system comprising a plurality of fluidic components connected in circuit and operated by pushbuttons and selector switches to provide continuous cycling of the press, single cycling of the press, and inching of the press, as well as emergency stopping and top stopping thereof.

United States Patent Inventor Philip V. Monnln Minster, Ohio 769,221 Oct. 21, 1968 Aug. 31, 1971 The Minster Machine Company Minster, Ohio Appl, No. Filed Patented Assignee FLUIDIC PRESS CONTROL SYSTEM 28 Claims, 3 Drawing Figs.

US. Cl. 100/53, l37/8l.5, 192/12 Int. Cl B30b 15/14 Field of Search 100/53,

[56] References Cited UNITED STATES PATENTS 3,191,611 6/1965 Bauer 137/81.5 3,258,023 6/1966 'Bowles.... 137/81.5 3,270,932 9/1966 Smith 137/81.5 X 3,507,212 4/1970 Matteson 100/53 Primary Examiner-Billy J. Wilhite Attorney-Jeffers and Rickert hlLllllDllC PRESS CUNTRQL SYSTEM This invention relates to controls for machines, particularly presses, and is especially concerned with a fluidic control system for presses.

Press controls are usually electrical in nature and the failure rate of the components is relatively high. Further, a shock hazard exists; the electrical components are bulky and expensive; and elements such as rotary switches and limit switches are usually included which wear and require maintenance.

The present invention has, as a particular objective, the provision of a press control system in which all of the drawbacks referred to above which are inherent in an electrical control system are eliminated.

Another particular object of the present invention is the provision of a fluidic control system for a press.

The nature of the present invention and the objects and advantages thereof will become apparent upon reference to the following detailed specification, taken in connection with the following drawings in which:

FIG. I is a schematic view of a mechanical press adapted for control by a system according to the present invention.

FIG. 2 is a fragmentary view showing a position detector for use with the system.

FIG. 3 is a schematic view of the entire fluidic control system.

SUMMARY OF THE INVENTION A mechanical press is provided with a pneumatically operated clutch-brake with a control valve controlling the supply of actuating fluid thereto. The control valve, in turn, is under the control of a fluidic system provided with pushbuttons and interlocks so the press can be operated on single cycle or continuous cycle. The system provides for emergency stopping and for inching of the press, all accomplished by the fluidic control system.

DETAILED DESCRIPTION In FIG. l, the press shown has a bed llt), head 12, uprights l4, and a slide 16 guided on the uprights. Connecting rods l8 connect slide 116 to crankshaft 20 which carries flywheel pulley 22 driven by belts 24 leading from flywheel pulley 22 to pulley 26 driven by motor Zli.

A pneumatically operated clutch-brake mechanism 30 is disposed between flywheel pulley 22 and crankshaft 20 and head 12 and when supplied with air under pressure clutches flywheel pulley 22 to crankshaft 20. When air is exhausted from the clutch-brake mechanism, it unclutches flywheel pulley 22 from the crankshaft Zll and sets a brake disposed between head 12 and crankshaft 20.

Bed rollingly receives the rolling bolster 32 on which is mounted lower part 34 of a die set, the upper part 36 of which is mounted on the underside of slide 16.

Conduit 3% leads to the clutch-brake mechanism 30 from the service part of a 3-way valve 40. Valve M) has a valve member 22 spring urged by a spring 4M to a normal position wherein conduit 38 is connected to exhaust conduit 46. A supply of air under pressure from conduit 63 to the top of piston 50 will cause valve member 42 to shift downwardly and connect conduit 38 to pressure conduit 52.

Conduit 52 leads to the service part of a second 3-way valve 56 having a shiftable valve member 56. A spring 58 normally holds valve member 56 in position to connect conduit 52 with conduit 60 which leads to compressed air source 62.

A supply of pressure from conduit 64 to the top of piston 66 will shift valve member 56 downwardly and connect conduit 52 with exhaust conduit 68.

The press is normally controlled by the shifting of valve member 42 and valve member 56 is only shifted under certain emergency conditions.

A detector valve 70 has a stem 72 which opens the valve for a supply of control pressure to a conduit 74 when valve member $2 is in its lower position. Valve It? is employed to indicate failure of the valve member 52 to shift to its clutchbrake exhausting position at the proper time. An alternate method in sensing a clutch or valve MP malfunction would be to sense a pressure in the conduit 3& and provide a positive signal to the line port 29 of element T.

As will be seen in FIG. 2, a further detector valve '76 is carried by bed ill and has a stem "iii adapted to be engaged by bolster 32 to close the valve when the bolster or tooling mechanism is in its proper stopped position against stop screw 80. When valve 76 is open pressure is supplied to conduit $2 and when valve "76 is closed pressure is out off from conduit $2. This is an optional or additional feature, and is not essential.

FIG. 3 shows the fluidic control system of the present invention. This system is made up, in the main, of known fluidic components such as or gates, and" gates, flip-flops, one shots, and other components. In FIG. 3, each component has a designating capital letter and the ports of the components are numbered. The following description refers to the ports by the letter of the pertaining component together with the port member. For example, A3 is the port marked 3 of component A. Each component has an inlet port for air under pressure at the top, one or more outlet ports at the bottom, and control ports on one or both sides. All of the components are shown by the symbols recommended by the National Fluid Power Association (NFPA).

In FIG. 3, PEI and P52 are pushbuttons which vent Al and B2 when the pushbuttons are released and block off the exhaust from All and B2 when the pushbuttons are depressed.

When PBl is depressed, the output from gate A shifts from Ail to A4 and a signal enters control port Cd of one shot C. A signal of fixed duration is supplied from port C9 to control port G9 of bistable flip-flop G. The output of G now shifts from G to G65 so that the signal to control port VW of the inhibited or" gate V is removed. If Hill is released, the output of A shifts back to A3 and a signal is supplied to control port E3 of the inhibited or gate E to cause its output to shift to E7 and supply a signal to control port G7 of G. The output of G then shifts to Gill to cause a signal to Vlli to cause the output of V to go to gate VIE.

Depressing of PB2 causes the same series of events to occur via B, D and H resulting in removal of the signal at Hi3. If IBll is released, H is reset by the signal from Fiji to H3 and the signal to I-Ill3 is resumed.

Since it is required that both of the signals at Glil and I'Illll must terminate to permit the output of V to shift from VEIS to Vlld, it will be apparent that both PBl and P82 must be depressed at the same time to get an output at V An output at V114 is delivered to conduit ieading to valve 46 and causes the valve ill to shift and start a press cycle. The output at V1.4 is also conveyed by conduit 11969 to control port SM of or gate S so its output shifts to which is connected to control port J28 of amplifier J. The signal at JZll causes the amplifier output to go to JCT and, is selector valve SVll is in continuous. position, the output form .lCT will be conveyed to control ports ECT and PCT of the aforementioned inhibited or" gates E and F. The signals of ECT and PCT prevail over signals at E3 and F5 so that when selector valve SVll is in continuous position, the press will continue to cycle once it is started by closing PB]. and IP52 at the same time.

To prevent false starting of the press when the air is turned on, a preference component K, which is an or gate that will supply its output to K26 until P131 is depressed and will thereafter supply its output to the terminal marked or" until the air supply is again out off. The output at I626 is supplied to one of the several control ports of or" gate L, namely, to port L264. A signal to any of the control ports of gate L causes its output to shift from L56 to L]. l. The output at loll supplies control ports Gill and Hlli of gates G and H and causes the respective outputs thereof to gotoGlii and H13, respectively. As described, a signal at either of Gllil or llli will cause the output of V to go to V1.5 and shut off the supply of air to conduit 48 and stop the press. K thus prevents any accidental tripping of the press when the air is first turned on.

If selector valve SVl is set in its single stroke position," there is a signal to ECT and FCT in the interval from 170- 350 of the press stroke. This is accomplished by a valve cam 102 driven by the press crankshaft and operable to supply air under pressure to conduit 104 from the time the press passes 170 to the time the press reaches 350. PB and P82 must be held closed until the press passes 170 and may thereafter be released or held down. In any case, once the press passes 170 it will continue for one full cycle and will then halt at the top 360 or position.

When the press reaches 350, the signal to control port U35 of or gate U is interrupted and the output of U goes from port U62 to port U36 from which it is supplied to port 136 of one shot T. The output pulse from ITPL goes to control ports ETPL and PTPL and causes outputs at E7 and F8 regardless of the position of PB] and PB2. A signal at either of E7 and F8 will interrupt the supply to conduit 48. Thus, with SVl set on single stroke, the press will make one stroke and stop at the top.

When SVl is set on inch, there is no signal to ECT or FCT so that flip-flops G and H are reset as soon as either of pushbuttons FBI or PBZ are released. Thus, the press can be moved into and stopped in any position when SVl is in inch position.

A second selector valve SV2 has a hand position wherein only pushbuttons FBI and P82 are effective and a second position wherein a foot switch 200 is effective for controlling gate 0. When foot switch 200 is depressed, a signal is supplied to control port 051A of gate 0 and the output of the gate shifts from 050 to 049. The output at 049 provides a signal to control ports A49 and B45) to shift the output gates A and B to ports A4 and B6 the same as if pushbuttonsPBl and P132 had been depressed. If the selector 8V] is on single stroke, the foot switch will act the same as when P131 and P82 are simultaneously pressed (previously described). If the selector SVl is on continuous upon pressing down and then releasing the foot switch, the output of 0 shifts back to 050 and a signal is sup plied to the control port 050 of one shot O which will cause the press to stop at the top of its stroke as will be described. If the foot switch 200 is held down, and SVl is on continuous, the press will continue to cycle. If SVl is on single stroke. even if switch 200 is held down, the press will perform only one cycle.

One mode of operating switch 200 on continuous is to depress the switch and then release it which will, as explained, start a press cycle and then trip one shot 0. The output from Q, at Q52, is delivered to control port N52 of gate N so the output from N will shift from N51 to N19. The output from N19 supplies a signal to control N19. P19 of the bistable flipflop P and shifics the output of P to P20.

The output from P20 supplies a signal to control port R20 of and" gate R. This signal, however, is effective only when there is also a signal at RTPL. This latter signal, derived from one shot 1, occurs when the press is at 350 of its stroke so that the output of R shifts to R18 only when the press is at the top of its stroke.

The output at R18 supplies a signal to control port L18 of or gate L to shift its output to L11 which will, as explained, reset G and H and stop the press.

It will be noted that there is a signal to control port U35 of gate U at 350 of every press cycle. When 8V] is set on continuous, however, the stronger signal at ECT and FCT inhibits the signal at ETPL and FT'PL so the press does not stop at the top of the stroke when started by P81 and PBZ or if foot switch 200 is held depressed.

The signal supplied by I to RTPL is effective only when there is also a signal at R20 and this will occur, in normal operation, only when foot switch 200 is depressed and then released.

A pushbutton marked TO? STOP" is provided which cam be depressed at any time to supply a signal to control port N21 of gate N to shift the output of N to N19 and thereby trip bistable flip-flop P to supply its output to P20 which will, in turn, supply a signal to R20 so the press will stop at the top of the cycle then in progress. The TOP STOP" pushbutton, therefore, will stop the press at the top of its stroke when it is on continuous cycle. Bistable P is reset by a signal from V15 switching output to P55 every time the circuit is in an off (stop) mode.

A further pushbutton, of which there may be several, marked EMERGENCY STOP, is provided for efiecting the immediate halting of the press in an emergency. Depressing of this pushbutton supplies a signal to control port M16 of gate 'M and shifts the output of gate M to M17. M17 supplies a signal directly to L17 which will result in immediate tripping of bistables G and H and halting of the press.

M17 also supplies a signal to control port W17 of the bistable flip-flop W and causes the output of W to go to W32 which results in a supply of compressed air to conduit 64 which will move valve 54 (FIG. 1) to exhaust position and interrupt the supply of clutch actuating compressed air to main control valve 40. This also allows the clutch to exhaust through the main valve 40 out the exhaust 68 of valve 54.

Gate W is overriding and operates in any mode of operation of the press and holds the press off until reset. Resetting of flip-flop W to shift its output to W33 can be accomplished by shutting off the air supply to the fluidic system and then restoring it and, whereupon, the preferential or" gate K will supply a signal from K26 to W26-2 to reset W.

In normal operation, however, W is reset by closing the pushbutton marked RESET which will cause a signal from R48 to W34.

W can also be tripped to cause its output to go to W32 and stop the press by a'signal to control port W30, derived from output port T30 of and" gate T. And gate T responds to a coincidence of signals at T152 and T29. The signal at Tl52 is derived from V15 via a delaying capacitor designated CAP. The signal at T29 is derived from conduit 74 leading to monitoring valve 70 (FIG. 1) which is closed only when valve member 42 of main control valve 40 is shifted into position to exhaust the clutch-brake mechanism 30 (FIG. 1). This can also be a pressure sensor in conduit 38, sensing if the clutch is operating (pressurized) when fluidic circuit says off. Gate T will, thus, be shifted so as to trip W to stop the press only when gate V has gone into condition to halt the press and valve member 42 has failed to shift. Capacitor CAP is provided to introduce a short time delay so that gate T is not effected during normal operation of the press but only when valve member 42 fails to shift.

Further interlocking controls may be provided, as desired, to prevent operation of the press when certain conditions are not met. For example, a valve 210 is normally closed but will be opened when a pressure-sensing element 212 senses inadequate lubrication pressure. When valve 210 opens, due to low lubrication pressure, a signal is supplied to control port P22 of bistable P which will result in stopping of the press at the top of its stroke. An indicator 214 is provided to indicate the condition of inadequate lubrication pressure.

Valve 76 (FIG. 2) is open when bolster 32 is not in proper position and supplies a signal via conduit 32 to control port L23 of gate L which will prevent tripping bistables G and H and will thus prevent starting of the press. Check valve 83 in conduit 82 is provided so that other signal supplies can be connected to control port L23. For example, a workpiece position detector arrangement could be providedand supply a signal to L23 if the workpiece was not in proper position.

A third selector valve SV3 has a circuit off" position wherein a signal is supplied to L23 via another check valve 85 so that the press cannot be run. Another, circuit on" position of valve SV3 removes the said signal and permits the press to be cycled in the various modes described above.

In FIG. 3, numeral d7 indicates a pressure switch and when pressure is supplied thereto the brake for the press is deenergized. Numeral M in FIG. 3 indicates a switch, or relay, which interrupts the energizing circuit for the press drive motor when pressure is supplied thereto. Pressure is supplied to switches id and 437 when switch blade d5 is closed on the terminal d2. Switch dd receives pressure when blade d5 is closed on the terminal marked circuit off." The switch blade in this position also supplied pressure to port 23 of the or gate L to switch bistables G and ii both to off position. When blade #35 engages the terminal circuit on," the press can be operated in the normal manner.

By placing switch blade l in engagement with terminal 42 which is marked bar only, the motor is deenergized and the press brake is disengaged. When the operator then pushes the button marked bar the press clutch will be energized and the press drive can then be manually operated.

when the control switch SW1 is set to inch position, the ball marked ball of inch selector closes a port in line 45a and, thus, supplies pressure to switch blade 4h. Pressure is also supplied to a switch marked REV and, at this time only, the motor can be run in the reverse direction. This occurs only when the press is being inched.

Modifications and adaptations may be made in the invention falling within the scope of the appended claims.

l. A control system for a press, said press having actuating element means shiftable to a first position to cause the press to cycle and to a second position to halt the press, fluid-operable means operatively associated with said actuating element means to effect the said shifting thereof and responsive to a supply of pressure fluid to shift said actuating element into its said first position, a source of control air under pressure, fluidic elements connected in circuit and supplied by said source of control air and including selectively operable switch means, and means under the control of said fluidic elements for controlling the supply of fluid to said fluid operable means to start the press and the exhausting of fluid from said fluid operable means to halt the press.

A control system according to claim 1 in which said fluidic elements include an OR gate having an ON outlet port operatively connected to said fluid operable means and also having an OFF outlet port not connected to said fluid-operable means, said Oil. gate also having a pair of OFF control ports, a signal at either said OFF control ports interrupting the output of said OR gate from said ON outlet port, said switch means including a first pushbutton controlling the signal to one oi said OFF control ports and a second pushbutton controlling the signal to the other of said 01F F control ports.

3. A control system according to claim 2 which includes a bistable flipflop between each said pushbuttons and the respective OFF control port of said OR gate, each flip-fiop having an OFF outlet port connected to the respective said OFF control port of said OR gate and also having a RUN outlet port, each said flip-flop having opposed RUN and OFF control port means and each thereof responsive to a signal for directing the output of the pertaining flip-flop respectively, to the RUN or OFF outlet port thereof, and means connecting each said pushbutton with the said control ports on one of said flip-flops so that depressing of the pushbutton will supply a signal to the RUN control port means of the respective flipilop while releasing of said pushbutton will supply a signal to the OFF control port means of the respective flip-flop whereby both of said pushbuttons must be depressed to remove both of the signals from the OFF control ports of said OR gate and start said press.

d. A control system according to claim 3 in which said control ports of the respective flip-flops includes a second OR gate for each pushbutton each having a pair of outlet ports, each second OR gate having control port means to which a signal is supplied when the pertaining pushbutton is depressed and from which the signal is removed when the pertaining pushbutton is released, each second OR gate having a first outlet port which receives the output of the respective gate when there is a signal at the respective control port means and a second outlet port which receives the said output when the signal to the respective control port means is terminated, at one shot element connecting each said first outlet port of each said second OR gate with said RUN control port or the respective said flip-flop, and a third OR gate having an outlet port connected to the OFF control port moms of each said flip liop and each said third OR gate having control port means sensitive to a signal for directing the output of the respect v third OR gate to its said outlet port for the duration at" said signal, the said control port means of each said third OR gate having connected to the said second outlet port of the respective said second OR gate.

5. A control system according to claim 4 in which each said third OR gate has a further inhibiting control port adapted when supplied with a signal to counteract the influence oi the signal supplied to the said control gate means of the respective third OR gate from the said second outlet port of the pertain ing said second OR gate upon release of the pertaining pushbutton, and a selector valve connected to said further control ports and having a first position wherein an inhibiting signal is continuously supplied through said selector valve to the said further control port of each said third OR gates while the press is running to prevent the supply of signal to said OlFlF control ports of said flip-flops upon release of said pushbuttons thereby to provide for continuous cycling of said press.

6. A control system according to claim 5 in which said selector valve has a second position wherein said continuous signal is interrupted, and press controlled means operable when said selector is in said second position for supplying a signal through said selector valve to said further control ports of said third OR gates, said signal commencing after the press is started and before the pushbuttons are released and terminating just before the top of the press stroke to stop the press at the top of its stroke.

A control system according to claim ti in which said press controlled means is in the form of a rotary cam driven by the press and operable to supply a signal to said selector valve in the range of about to about 350 oi the press stroke when considering an entire press stroke to amount to 360.

A control system according to claim 7 which said selector valve has a third position in which no signal is supplied to the said further control parts of said third OR gates to provide for halting of the press in any position thereof immediately upon releasing of either or both of said pushbuttons.

9. A control system according to claim 5 wherein an amplifier is provided for supplying said inhibiting signal to said selector valve when the latter is in its said first position, said amplifier having a first outlet port connected to said selector valve and also having a second outlet port, said amplifier hav ing a first control port sensitive to a signal for directing the amplifier output to said first outlet port and a second control port sensitive to a signal for directing said amplifier output to said second outlet port, a fourth OR gate having a first outlet port connected to said first control port of said amplifier and a second outlet port connected to said second control port of said amplifier and said fourth OR gate having a controi port sensitive to a signal to direct the output thereof to said first outlet port thereof, said control port of said fourth OR gate being connected to said ON outlet port of the first mentioned OR gate to receive a signal therefrom whenever the press is running.

MD. A control system according to claim 6 which includes a fifth OR gate having first and second outlet ports and a control port sensitive to a signal for directing the output thereof to said second outlet port while the output is directed to said first outlet port in the absence of a signal at said control port, a further one-shot element connected to said one outlet port of said fifth OR gate and having an outlet port, said outlet port of said further one-shot element being connected to said control port means of said third OR gate, and the control port of said fifth OR gate being connected to press controlled means to receive a signal therefrom over the interval from about 170 to about 350 of the press stroke whereby with the said selector valve in its said second position, the press will be halted at the top of its stroke even when the pushbuttons are in depressed position.

11. A control system according to claim which includes a sixth OR gate having first and second outlet ports, said OFF control port means of said flip-flops being connected to said first outlet port of said sixth OR gate, control port means for said sixth OR gate sensitive to a signal to direct the output of said sixth OR gate to the first said outlet port thereof, and signal supply means for supplying signals to said control port means of said sixth OR gate whereby thepress can be stopped at any time by a signal to the control port means of said sixth OR gate.

12. A control system according to claim 11 in which said press includes a tooling mechanism and said signal supply means includes a valve operable to supply a signal to said control port means of said sixth OR gate when the bolster is out of working position while terminating said signal when the bolster is in working position.

13. A control system according to claim 11 which includes a preferencing element having an outlet port connected to said control port means of said sixth OR gate, said preferencing element having a control port sensitive to a signal to divert the output of the preferencing element away from said outlet port and said element including means to maintain the output so diverted until the supply of air to the system is shut off, and said control port of said preferencing element being connected to receive a signal from the said first outlet port of one of said second OR gates upon depressing of the respective pushbutton whereby accidental starting of the press upon turning the air supply on for the control system is prevented.

14. A control system according to claim 4 in which said switch meansincludes foot switch means operable independently of said pushbutton for supplying a signal to said control port means of said second OR gates and a second selector valve adjustable for making said foot switch means selectively effective and ineffective.

15. A control system according to claim 14 which includes a seventh OR gate having a first outlet port normally receiving the output therefrom and a second outlet port and control port means sensitive to a signal to direct the said output to said second outlet port, said foot switch means controlling the: signal to the control port of said seventh OR gate and said second outlet port thereof being connected to said control port means of said second OR gate, a third one-shot element: connected to receive the output from said first outlet port 01 said seventh OR gate and having an outlet port at which a signal is developed only for a certain period upon release of said foot switch means after depressing thereof, an AND gate having a first outlet port normally receiving the output thereof, said AND gate having a second outlet port connected to said control port means of said sixth OR gate, said AND gate having a pair of control ports operable during the simultaneous supply of signals thereto to direct the output of said AND gate to said second outlet port, means responsive to the signal from said outlet port of said third one-shot element for establishing a signal to one of the control ports of said AND gate, and means for supplying a signal to the other control port of said AND gate as the press approaches the top of its stroke.

16. A control system according to claim 15 in which said last mentioned means comprises an eighth OR gate having an outlet port and control port means operable while supplied with a signal to direct the output of the gate to said outlet port, said control port means of said eighth OR gate being connected to the outlet port of said third one shot element, a third flip-flop element having a first outlet port connected to said one control port of said AND gate and also having a second outlet port, said third flip-flop element having control port means sensitive to a signal for switching the output thereof to said first outlet port and a further control port sensitive to a signal to switch the output of said. third flip-flop element to said second outlet port.

17. A control system according to claim 16 which includes a third top stop" pushbutton connected to the control port means of said eighth OR gate and operable when actuated to supply a signal to the said control port means to provide for stopping the press when it is on continuous cycle, said press stopping at the top of its stroke when stopped by actuation of said third pushbutton.

18. A control system according to claim l5 in which said further control port of said third flip-flop element is connected to said OFF outlet port of the first mentioned OR gate to provide for switching the output to its said second outlet port of said third flip-flop element when the press stops.

19. A control system according to claim 1 1 which includes a ninth OR gate having an outlet port connected to said control port means of said sixth OR gate and having a control port operable during the supply of a signal thereto to direct the output of said ninth OR gate to said outlet port, and a fourth emergency stop pushbutton connected to the said control port of said ninth OR gate and operable to supply a signal thereto when actuated thereby to provide for immediate stopping of the press upon actuation of said fourth pushbutton.

20. A control system according to claim 18, which includes a ninth OR gate having an outlet port connected to said control port means of said sixth OR gate and having a control port operable during the supply of a signal thereto to direct the outputof said ninth OR gate to said outlet port, and a fourth emergency stop pushbutton connectedtothe said control port of said ninth OR gate and operable to supply a signal thereto when actuated thereby to provide for immediate stopping of the press upon actuation of said fourth pushbutton.

21. A control system according to claim 20 in which said actuating element means includes a normally closed main valve having first fluid operable means responsive to pressure to move the valve to open position and operatively connected to said ON outlet port of said first mentioned OR gate and a normally open valve in series with said main valve and having second fluid operable means responsive to pressure to move the valve to closed position and, said systemincluding a fourth flip-flop element having a first outlet port connected to said second fluid operable means and also having a second discharge port, said fourth flip-flop element having first control port means operable upon receiving a signal to switch the output thereof to said first outlet port and second control port means operable upon receiving a signal to switch the output thereof to said second outlet port, said outlet port of said ninth OR gate being connected to said first control port means to cause interruption of the supply of pressure fluid to said valves.

22. A control system according to claim 21 in which said outlet port of said preferencing element is connected to said second control port means of said fourth flip-flop element so that upon initiation of the supply of control air to said system, the output of said fourth flip-flop will be switched to its said second outlet port.

23. A control system according to claim 22 which includes a manual switch connecting said second control port means of said fourth flip-flop element with said first outlet port of said AND gate to provide for switching of the output of said fourth fiip-fiop element to its said second outlet port after emergency stopping of the press.

24. A control system according to claim 22. which includes means operated by said main valve fordeveloping an emergency signal upon failure of said main valve to shift out of its open position when the supply of fluid to its said first fluid operable means is interrupted, a second AND gate having a discharge port connected to said first control port means of said fourth flip-flop element and a pair of control ports operable upon the simultaneous supply of signals thereto to direct the output of the second AND gate to its said outlet port, one

, of said control ports being connected to receive said emergency signal and the other of said control ports being connected to the OFF outlet port of said first mentioned OR gate whereby said press will halt immediately upon failure of said main valve to shift to closed position when the output of said first mentioned OR gate goes to the OFF outlet port.

25. A control system according to claim 24 which includes a capacitor interposed between said OFF port of said first mentioned OR gate and the said other control port of said second AND gate to introduce a delay to prevent operation of the second AND gate in normal operation of the press.

26. A control system according to claim 25 in which said press comprises a reversible drive motor, reversing means to effect reversal of said motor, and means operated by movement of said first mentioned selector switch to inch" position to permit said reversing means to be operated.

27. A control system according to claim 26 which includes a third selector valve having a first idle position and also having a second position wherein a signal is supplied to a control port of said sixth OR gate to halt said press, a main control switch operable into open position by pressure, and said third selector valve supplying pressure to said main control switch in its said second position.

28. A control system according to claim 27 in which said third selector valve has a third position wherein the signal to said sixth OR gate is interrupted while the supply of pressure to said main control switch continues, said press having a brake, pressure means to open the brake, said selector valve supplying pressure to said pressure means when in its third position, and a bar valve selectively operable when said third selector valve is in its third position for supplying a signal to said first mentioned OR gate to shift the output thereof to its said RUN port.

*zg l g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 135 Dated August 31, 1971 Inventor(s) P lip V. Monnin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

T- Col. 2, line 57, "is" should be if Col. 2, line 58, "form" should be from Col. 3, line 35, "of" omitted between "output" and gates".

Col. 3, line 54, "N19. should be deleted and port 19 inserted.

Col. 4, line 2 "cam" should be can Col. 5, just before the claims, the following omitted 'What is claimed is" Col. 5, lines 68 and 69 (Claim 4) "means connecting each of said pushbuttons with said" omitted between "said" and "control".

Col. 6, line 25 (Claim 5) "a" omitted between "of" and "signal".

C01. 10, line 4 (Claim 27) "when" omitted be tween "switch" anC HinH' Signed and sealed this 29th day of February 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. A control system for a press, said press having actuating element means shiftable to a first position to cause the press to cycle and to a second position to halt the press, fluid-operable means operatively associated with said actuating element means to effect the said shifting thereof and responsive to a supply of pressure fluid to shift said actuating element into its said first position, a source of contRol air under pressure, fluidic elements connected in circuit and supplied by said source of control air and including selectively operable switch means, and means under the control of said fluidic elements for controlling the supply of fluid to said fluid operable means to start the press and the exhausting of fluid from said fluid operable means to halt the press.
 2. A control system according to claim 1 in which said fluidic elements include an OR gate having an ON outlet port operatively connected to said fluid operable means and also having an OFF outlet port not connected to said fluid-operable means, said OR gate also having a pair of OFF control ports, a signal at either said OFF control ports interrupting the output of said OR gate from said ON outlet port, said switch means including a first pushbutton controlling the signal to one of said OFF control ports and a second pushbutton controlling the signal to the other of said OFF control ports.
 3. A control system according to claim 2 which includes a bistable flip-flop between each said pushbuttons and the respective OFF control port of said OR gate, each flip-flop having an OFF outlet port connected to the respective said OFF control port of said OR gate and also having a RUN outlet port, each said flip-flop having opposed RUN and OFF control port means and each thereof responsive to a signal for directing the output of the pertaining flip-flop respectively, to the RUN or OFF outlet port thereof, and means connecting each said pushbutton with the said control ports on one of said flip-flops so that depressing of the pushbutton will supply a signal to the RUN control port means of the respective flip-flop while releasing of said pushbutton will supply a signal to the OFF control port means of the respective flip-flop whereby both of said pushbuttons must be depressed to remove both of the signals from the OFF control ports of said OR gate and start said press.
 4. A control system according to claim 3 in which said control ports of the respective flip-flops includes a second OR gate for each pushbutton each having a pair of outlet ports, each second OR gate having control port means to which a signal is supplied when the pertaining pushbutton is depressed and from which the signal is removed when the pertaining pushbutton is released, each second OR gate having a first outlet port which receives the output of the respective gate when there is a signal at the respective control port means and a second outlet port which receives the said output when the signal to the respective control port means is terminated, a one shot element connecting each said first outlet port of each said second OR gate with said RUN control port of the respective said flip-flop, and a third OR gate having an outlet port connected to the OFF control port means of each said flip-flop and each said third OR gate having control port means sensitive to a signal for directing the output of the respective third OR gate to its said outlet port for the duration of said signal, the said control port means of each said third OR gate having connected to the said second outlet port of the respective said second OR gate.
 5. A control system according to claim 4 in which each said third OR gate has a further inhibiting control port adapted when supplied with a signal to counteract the influence of the signal supplied to the said control gate means of the respective third OR gate from the said second outlet port of the pertaining said second OR gate upon release of the pertaining pushbutton, and a selector valve connected to said further control ports and having a first position wherein an inhibiting signal is continuously supplied through said selector valve to the said further control port of each said third OR gates while the press is running to prevent the supply of signal to said OFF control ports of said flip-flops upon release of said pushbuttons thereby to proVide for continuous cycling of said press.
 6. A control system according to claim 5 in which said selector valve has a second position wherein the said continuous signal is interrupted, and press controlled means operable when said selector is in said second position for supplying a signal through said selector valve to said further control ports of said third OR gates, said signal commencing after the press is started and before the pushbuttons are released and terminating just before the top of the press stroke to stop the press at the top of its stroke.
 7. A control system according to claim 6 in which said press controlled means is in the form of a rotary cam driven by the press and operable to supply a signal to said selector valve in the range of about 170* to about 350* of the press stroke when considering an entire press stroke to amount to 360*.
 8. A control system according to claim 7 in which said selector valve has a third position in which no signal is supplied to the said further control parts of said third OR gates to provide for halting of the press in any position thereof immediately upon releasing of either or both of said pushbuttons.
 9. A control system according to claim 5 wherein an amplifier is provided for supplying said inhibiting signal to said selector valve when the latter is in its said first position, said amplifier having a first outlet port connected to said selector valve and also having a second outlet port, said amplifier having a first control port sensitive to a signal for directing the amplifier output to said first outlet port and a second control port sensitive to a signal for directing said amplifier output to said second outlet port, a fourth OR gate having a first outlet port connected to said first control port of said amplifier and a second outlet port connected to said second control port of said amplifier and said fourth OR gate having a control port sensitive to a signal to direct the output thereof to said first outlet port thereof, said control port of said fourth OR gate being connected to said ON outlet port of the first mentioned OR gate to receive a signal therefrom whenever the press is running.
 10. A control system according to claim 6 which includes a fifth OR gate having first and second outlet ports and a control port sensitive to a signal for directing the output thereof to said second outlet port while the output is directed to said first outlet port in the absence of a signal at said control port, a further one-shot element connected to said one outlet port of said fifth OR gate and having an outlet port, said outlet port of said further one-shot element being connected to said control port means of said third OR gate, and the said control port of said fifth OR gate being connected to said press controlled means to receive a signal therefrom over the interval from about 170* to about 350* of the press stroke whereby with the said selector valve in its said second position, the press will be halted at the top of its stroke even when the pushbuttons are in depressed position.
 11. A control system according to claim 5 which includes a sixth OR gate having first and second outlet ports, said OFF control port means of said flip-flops being connected to said first outlet port of said sixth OR gate, control port means for said sixth OR gate sensitive to a signal to direct the output of said sixth OR gate to the first said outlet port thereof, and signal supply means for supplying signals to said control port means of said sixth OR gate whereby the press can be stopped at any time by a signal to the control port means of said sixth OR gate.
 12. A control system according to claim 11 in which said press includes a tooling mechanism and said signal supply means includes a valve operable to supply a signal to said control port means of said sixth OR gate when the bolster is out of working position while terminating saId signal when the bolster is in working position.
 13. A control system according to claim 11 which includes a preferencing element having an outlet port connected to said control port means of said sixth OR gate, said preferencing element having a control port sensitive to a signal to divert the output of the preferencing element away from said outlet port and said element including means to maintain the output so diverted until the supply of air to the system is shut off, and said control port of said preferencing element being connected to receive a signal from the said first outlet port of one of said second OR gates upon depressing of the respective pushbutton whereby accidental starting of the press upon turning the air supply on for the control system is prevented.
 14. A control system according to claim 4 in which said switch means includes foot switch means operable independently of said pushbutton for supplying a signal to said control port means of said second OR gates and a second selector valve adjustable for making said foot switch means selectively effective and ineffective.
 15. A control system according to claim 14 which includes a seventh OR gate having a first outlet port normally receiving the output therefrom and a second outlet port and control port means sensitive to a signal to direct the said output to said second outlet port, said foot switch means controlling the signal to the control port of said seventh OR gate and said second outlet port thereof being connected to said control port means of said second OR gate, a third one-shot element connected to receive the output from said first outlet port of said seventh OR gate and having an outlet port at which a signal is developed only for a certain period upon release of said foot switch means after depressing thereof, an AND gate having a first outlet port normally receiving the output thereof, said AND gate having a second outlet port connected to said control port means of said sixth OR gate, said AND gate having a pair of control ports operable during the simultaneous supply of signals thereto to direct the output of said AND gate to said second outlet port, means responsive to the signal from said outlet port of said third one-shot element for establishing a signal to one of the control ports of said AND gate, and means for supplying a signal to the other control port of said AND gate as the press approaches the top of its stroke.
 16. A control system according to claim 15 in which said last mentioned means comprises an eighth OR gate having an outlet port and control port means operable while supplied with a signal to direct the output of the gate to said outlet port, said control port means of said eighth OR gate being connected to the outlet port of said third one shot element, a third flip-flop element having a first outlet port connected to said one control port of said AND gate and also having a second outlet port, said third flip-flop element having control port means sensitive to a signal for switching the output thereof to said first outlet port and a further control port sensitive to a signal to switch the output of said third flip-flop element to said second outlet port.
 17. A control system according to claim 16 which includes a third ''''top stop'''' pushbutton connected to the control port means of said eighth OR gate and operable when actuated to supply a signal to the said control port means to provide for stopping the press when it is on continuous cycle, said press stopping at the top of its stroke when stopped by actuation of said third pushbutton.
 18. A control system according to claim 15 in which said further control port of said third flip-flop element is connected to said OFF outlet port of the first mentioned OR gate to provide for switching the output to its said second outlet port of said third flip-flop element when the press stops.
 19. A control system according to claim 11 which includes a ninth OR gate having an outlet port connected to said control port means of said sixth OR gate and having a control port operable during the supply of a signal thereto to direct the output of said ninth OR gate to said outlet port, and a fourth ''''emergency stop'''' pushbutton connected to the said control port of said ninth OR gate and operable to supply a signal thereto when actuated thereby to provide for immediate stopping of the press upon actuation of said fourth pushbutton.
 20. A control system according to claim 18, which includes a ninth OR gate having an outlet port connected to said control port means of said sixth OR gate and having a control port operable during the supply of a signal thereto to direct the output of said ninth OR gate to said outlet port, and a fourth ''''emergency stop'''' pushbutton connected to the said control port of said ninth OR gate and operable to supply a signal thereto when actuated thereby to provide for immediate stopping of the press upon actuation of said fourth pushbutton.
 21. A control system according to claim 20 in which said actuating element means includes a normally closed main valve having first fluid operable means responsive to pressure to move the valve to open position and operatively connected to said ON outlet port of said first mentioned OR gate and a normally open valve in series with said main valve and having second fluid operable means responsive to pressure to move the valve to closed position and, said system including a fourth flip-flop element having a first outlet port connected to said second fluid operable means and also having a second discharge port, said fourth flip-flop element having first control port means operable upon receiving a signal to switch the output thereof to said first outlet port and second control port means operable upon receiving a signal to switch the output thereof to said second outlet port, said outlet port of said ninth OR gate being connected to said first control port means to cause interruption of the supply of pressure fluid to said valves.
 22. A control system according to claim 21 in which said outlet port of said preferencing element is connected to said second control port means of said fourth flip-flop element so that upon initiation of the supply of control air to said system, the output of said fourth flip-flop will be switched to its said second outlet port.
 23. A control system according to claim 22 which includes a manual switch connecting said second control port means of said fourth flip-flop element with said first outlet port of said AND gate to provide for switching of the output of said fourth flip-flop element to its said second outlet port after emergency stopping of the press.
 24. A control system according to claim 22 which includes means operated by said main valve for developing an emergency signal upon failure of said main valve to shift out of its open position when the supply of fluid to its said first fluid operable means is interrupted, a second AND gate having a discharge port connected to said first control port means of said fourth flip-flop element and a pair of control ports operable upon the simultaneous supply of signals thereto to direct the output of the second AND gate to its said outlet port, one of said control ports being connected to receive said emergency signal and the other of said control ports being connected to the OFF outlet port of said first mentioned OR gate whereby said press will halt immediately upon failure of said main valve to shift to closed position when the output of said first mentioned OR gate goes to the OFF outlet port.
 25. A control system according to claim 24 which includes a capacitor interposed between said OFF port of said first mentioned OR gate and the said other control port of said second AND gate to introduce a delay to prevent operation of the second AND gate in normal operation of the press.
 26. A control system according to claim 25 in Which said press comprises a reversible drive motor, reversing means to effect reversal of said motor, and means operated by movement of said first mentioned selector switch to ''''inch'''' position to permit said reversing means to be operated.
 27. A control system according to claim 26 which includes a third selector valve having a first idle position and also having a second position wherein a signal is supplied to a control port of said sixth OR gate to halt said press, a main control switch operable into open position by pressure, and said third selector valve supplying pressure to said main control switch in its said second position.
 28. A control system according to claim 27 in which said third selector valve has a third position wherein the signal to said sixth OR gate is interrupted while the supply of pressure to said main control switch continues, said press having a brake, pressure means to open the brake, said selector valve supplying pressure to said pressure means when in its third position, and a bar valve selectively operable when said third selector valve is in its third position for supplying a signal to said first mentioned OR gate to shift the output thereof to its said RUN port. 